At present, a fuel injection environment simulation method is generally used to detect a piston fuel injector in car plants. In this method, a fuel injection nozzle is mounted on a test bed in a same environment as that of an inner chamber of an engine, and is caused to inject fuel. If the fuel which is injected out reaches a predetermined position, it is considered to be qualified. The disadvantages of the detecting method include wasting time and labor as well as human cost, and polluting the environment in a workshop.